Pushing device for shifting mining machinery



1960 w. H. BARRETT 2,948,508

PUSHING DEVICE FOR SHIFTING MINING MACHINERY Filed March 17. 1958 23 F G I /7 FIG. 2.

F Y? M INVENTQR United States Patent O PUSHING DEVICE FOR SHIFTING MINING MACHINERY Wesley Horace Barrett, Cinderford, England, assignor to Dowty Mining Equipment Limited, Tewkesbury, England, a British company Filed Mar. 17, 1958, Ser. No. 721,931 Claims priority, application Great Britain Mar. 15, 19 57 8 Claims. (Cl. 254-35) This invention relates to pushing devices for shifting mining machinery such as conveyors which have to be periodically advanced towards the working face of the mine, the pushing device being of the kind comprising a strut also known as a stell, arranged to be jammed between the mine floor and roof and a pushing jack con-' nected between the stell and the mining machine so that reaction of the jack acts to: jam the stell more tightly between the fioor and the roof.

The main object of the invention is to facilitate the operations of setting the strut against the roof, releasing the strut and pulling it over the mine floor to a new position by means of the jack.

According to the present invention the strut is provided with a base frame or shoe having a convey surface adapted to rock the strut on the mine floor in a vertical plane in the line of advance when jamming and releasing the strut and to slide over the floor when pulled forward.

The pushing device according to the invention may comprise a strut having a head formed for gripping engagement with the mine roof and a base frame formed with a convex shoe or sole plate capable of rocking and sliding on the floor, a hydraulic jack extending freely and substantially horizontally through the base frame, a link or links extending forwardly from the rear end of the jack to a connection on the base frame, and fastening means on the forward end of the jack arranged for connection to the mining machine. By virtue of the link connection between the base frame and the jack cylinder and the free clearance of the latter within the former, the jack will freely adjust itself in height and inclination to the horizontal, regardless of rocking of the shoe upwardly as the strut tilts. Also by virtue of this linkage the jack can have a sufficiently long stroke while the head of the strut is embedded in the roof well forward of the waste area.

The shoe or sole plate is preferably of shallow smooth curvature which provides an adequate bearing surface against the floor and which acts as a skid for movement either backwards when the jack is set to push, or forwards when the device is advanced by contracting the jack, the mining machinery then constituting an anchor.

An example of the invention is illustrated on the accompanying drawings in which:

Figures 1, 2 and 3 are respectively a plan, an elevation and in part a front view and in part a section of a conveyor pusher at the line III-III of Figure 2.

Referring to the drawings, the strut comprises two telescopic tubes 1 and 2 adjustable for length by means of a pin and hole device 3. The upper tube is surmounted by a spike 4 and a disc 5, the former being designed to penetrate and the latter to resist excessive penetration of the roof. The lower tube 2 is welded to a base frame 6, also of welded construction comprising side plates 7 and 8, a cross-bar 9, a curved sole plate 10 and buttress webs 11 and 12.

A telescopic jack 13, usually hydraulically operated, has its piston rod 14 connected by a pivoted joint 15 to a con- 2,948,508 Patented Aug. 9, 1960 veyor element 16, and it extends substantially horizontally through the base frame 6, the rear end of the jack cylinder 17 being connected through a crosshead 18 to a pair of links 23 which extend forwardly at opposite sides of the jack to pivot pins 19 at the heel of the base frame 6.

The top of the jack is protected by a shroud 20 and carries forwardly a cover plate 21 which extends over a valve control box 22 through which connection is made in a known manner to the jack from hydraulic supply and return lines (not shown).

The sole plate 10 extends laterally on each side of the plates 7 and 8 to provide an adequate bearing surface against the floor, and its convexity is such that the strut can rock back and forth when setting and releasing and can also act as a skid for movement over the mine floor. It will, of course, be understood that the convexity of the sole plate is in a Vertical plane containing the line of advance and that the strut is not required to rock laterally. lt is not connected to the jack other than through the links 23.

The tubular portion of the strut is inclined backwardly from the radius which is struck to the center of the curved sole plate, this inclination being at approximately the preferred jamming angle of the strut to the normal to the roof. The sole plate 10 is slotted or furcated to approximately half its depth from the front end so that the jack cylinder in certain of its positions drops partly into the slot but rests on the unslotted rear portion whose slightly raised margin is shown by the dotted line 24 in Figure 1. When the jack is not under load, the weight ofthe jack will therefore tend to hold the strut at a greater inclination to the vertical than the required jamming angle, with the head clear of the roof and the pivot pins 19 below the axis of the jack, this position being shown by the chain r lines in Figure 2. The spike 4 of the head may then be engaged with the roof by rocking the base frame forwardly and the strut upwardly. This is done by setting the control valve in the valve control box 22. to extend and, if necessary, assisting the swinging by foot pressure on the forwrad part of the sole plate, or by hand pressure behind the tube 2.

After the base frame rocks forward, the links 23 may pull the base frame rearwardly to a small extent as the spike 4 bites into the roof, and after the strut has jammed further extension of the jack operates to push the conveyor forwardly, reacting from the jam strut. On releasing and contracting the jack, the links push the base frame 6 forward, sliding and rocking on its sole plate, thereby Withdrawing the spike 4 from the roof, after which the strut sways backwards clear of the roof during the forward movement.

The joint 15 on the forward end of the jack rod desirably comprises a universal joint which allows for normal variations in lateral and up and down displacement of the pushing device with respect to the conveyor element 16 on which it works. The hydraulic supply for the jack is conveniently taken through connections (not shown) on the outer end of the rod, which connections extend through the jack piston rod to the working chambers at opposite ends of the jack cylinder. The valve control box 22 may include a three position open-centre control valve for the jack.

As a further means of assisting in staking the strut after the spike 4 engages the roof, the strut may itself incorporate a hydraulic jack of known type within the tubes 1 and 2, valve means and suitable connections (not shown) being provided in such case to charge and release this jack at the appropriate times.

I claim as my invention:

1. A pushing device for shifting floor-supported mining machinery horizontally across the floor of a mine, comprising a horizontally disposed pushing jack arranged at one end for connection to such mining machinery, a generally upright strut formed at its lower end with a base frame convex at its floor-engaging surface, disposed to rock upon such surface in a vertical plane which includes the jack, and to slide over the floor, linkage means interconnecting the end of the jack opposite the latters machinery-engaging end and the adjacent portion of the convex base frame, for rocking of the strut without vertical displacement of the jack, and the strut being of a length to jam its upper end into the mine roof when rocked uprightly upon such convex surface, and to disengage the roof and slide its base frame over the floor when rocked downwardly.

2. A pushing device for shifting floor-supported mining machinery horizontally across the floor of a mine, comprising a horizontally disposed pushing jack arranged at one end for connection to such mining machinery, a generally upright strut rockably connected to the opposite end of said jack and formed with a base frame convex at its floor-engaging surface, to rock upon such surface in a vertical plane which includes the jack, and to slide over the floor, the toe of the convex surface nearer the mining machinery being farther from the upper end of the strut than the distant heel of the convex surface, the jack and the strut being connected at such heel, and the strut being of a length to jam its upper end into the mine roof when rocked uprightly onto its toe, and to disengage the roof and slide over the mine floor when rocked towards its heel.

3. A pushing device as in claim 2, including generally horizontal linkage means intermediate and pivotally connected to each of the jack, at its end distant from the mining machinery, and the heel of the convex surface.

4. A pushing device as in claim 3, wherein the shape of the convex surface and the point of connection of the linkage means to its heel are such that when the struts upper end is jammed against the mine roof and the strut has risen upon its toe, the linkage means is substantially aligned with the jack.

5. A pushing device as in claim 3, wherein the convex surface underlies the jack, and is slotted at its toe end for support of the jack when the strut is downswung from its jammed position.

6. A pushing device for shifting mining machinery comprising a strut, a head on the strut shaped for gripping engagement with the mine roof, a base frame having a convex lower skid surface enabling said frame to rock back and forth on the mine floor and to act as a skid thereon, the strut being rigidly joined to the base and extending along a line which is rearwardly inclined relative to a radius struck to the centre of the convex lower surface, and a pushing jack having telescopic elements one of which is pivotally connected to the base frame and the other of which is adapted for connection with the mining machine.

7. A pushing device for shifting mining machinery comprising a strut, a head on the strut shaped for gripping engagement with the mine roof, a base frame having a convex lower skid surface enabling said frame to rock back and forth on the mine floor and to act as a skid thereon, the strut being rigidly joined to the base and extending along a line which is rearwardly inclined to the radius struck to the centre of the convex lower surface, a pushing jack having a piston rod adapted for connection with the mining machine and a cylinder extending to the rear of the base frame, and a link pivotally connected to the rear end of the cylinder, said link extending forwardly to a pivotal connection between the link and the base frame.

8. A pushing device as in claim 7, wherein the base frame comprises side members between which the pushing jack cylinder extends, and a curved sole plate bridging the side members and providing the convex lower surface, the sole plate having front and rear edges which with the weight of the cylinder resting thereon maintain the strut substantially at a predetermined inclination at which the head is out of engagement with the mine roof.

References Cited in the file of this patent UNITED STATES PATENTS 

